HR: 11:25h
AN: V11G-05 INVITED     [PDF]
TI: The Hilina Slump: Consequences of Slope Failure and Volcanic Spreading Along the Submarine South Flank of Kilauea Volcano, HI
AU: * Morgan, J K
EM: morganj@rice.edu
AF: Rice University, Dept of Earth Science, 6100 Main Street, Houston, TX 77005
AU: Moore, G F
EM: gmoore@hawaii.edu
AF: University of Hawaii, Dept of Geology and Geophysics, 1680 East West Road, Honolulu, Hi 96822
AU: Clague, D A
EM: clague@mbari.org
AF: Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039
AB: Kilauea volcano is the type locale to study the dynamic interplay between slope failure and volcanic spreading; this was recognized very early by Jim Moore and colleagues. New geophysical data and seafloor mapping in the area now better resolve the dramatic history of Kilauea volcano. In this seismically active setting, the interface between the oceanic crust and volcanic edifice accommodates seaward sliding of the south flank of Kilauea, probably rooted along Kilauea's East Rift Zone. Present day displacement of the south flank is punctuated by intermittent movement of the Hilina slump, defined by a set of arcuate normal faults that break the flank just downslope of Kilauea's summit. Analysis of recent multichannel seismic (MCS) data and high-resolution bathymetry over the submarine slopes of Kilauea volcano reveals that the active slump has a relatively shallow detachment, 3-5 km deep, comprises largely slope sediments, and is restricted to the upper northwestern portion of the mobile south flank. Offset morphologic features along the marginal ridge known as Papa'u seamount, constrain measurable downslope displacement of the slump to ~3 km, directed oblique to its western boundary. The MCS data also reveal the buried scar of a large-scale slope failure to the northeast of the submarine Hilina slump, which is the probable source of thick deposits of volcaniclastic breccias presently contained within the frontal midslope bench. The midslope bench developed as the mobile south flank of Kilauea plowed seaward into and offscraped the landslide debris, trapping a broad basin above the landslide scar. Uplift and back-tilting of young basin fill indicate recent, and possibly ongoing, bench growth. The Hilina slump now impinges upon this frontal bench, a buttress that may tend to reduce the likelihood of future catastrophic detachment of the landslide.
DE: 3022 Marine sediments--processes and transport
DE: 3025 Marine seismics (0935)
DE: 8015 Local crustal structure
DE: 8122 Dynamics, gravity and tectonics
DE: 8400 VOLCANOLOGY
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting